This invention relates generally to self-cleaning oven door locks and more particularly to door locks wherein the act of closing the oven door actuates a switch the actuator of which is centrally located relative to the front of the oven frame.
The walls of the cooking chamber of conventional gas or electric ovens collect deposits from items cooked in the oven. Modern self-cleaning ovens reduce these deposits to dust with high heat when a self-cleaning cycle is initiated by a user. This cleaning method is commonly known as pyrolytic cleaning. The high temperature used for pyrolytic cleaning poses a hazard if the oven door is opened during the cleaning cycle. To prevent this, an oven door lock is employed.
Many types of oven door locks have been provided that lock the oven door for a period sufficient to complete a pyrolytic cleaning cycle. Typically, such ovens include a switch actuated by closure of the oven door that energizes or enables a driver circuit for locking the oven door. Many of these door locks use electrical motors, electromechanical machines or manual manipulation of mechanisms to move a latch to a position in which the latch prevents the oven door from being opened during a self-cleaning cycle. Examples of such locks are disclosed in Eff, U.S. Pat. No. 3,569,670; Gilliom, U.S. Pat. No. 3,859,979; Drouin, U.S. Pat. No. 4,109,637; Barnett, U.S. Pat. No. 4,374,320; Genbauffe et al., U.S. Pat. No. 4,927,996 and Smith, U.S. Pat. No. 6,302,098.
Smith, U.S. Pat. No. 6,302,098 discloses an oven door latch assembly with a motor and a switch located in a rearward position and a latch mounted for pivotal and longitudinal movement between an unlatched position, a latched position and a latched and sealed or pulled-in position. Smith uses a bias spring to bias the latch toward the unlatched position. The unnumbered switch in Smith does not appear to be a switch that actuates the motor drive circuitry but rather appears to be a switch that is actuated by a cam driven by the motor. Such switches tend to provide a change of state signal to a pyrolytic oven controller indicating that the oven is currently locked.
Ovens using latching mechanisms similar to that disclosed in Smith typically include a switch that actuates the drive circuitry for the motor so that it can move the latch into the latched position only when door is closed. Thus, upon receipt of a request to initiate a cleaning cycle, the motor can rotate the latch to seal and lock the oven. Some such ovens use a switch mounted near the front of the oven with a plunger extending forwardly beyond the frame so that it can be depressed by the door during closure to actuate the drive circuitry. Such switches must be heat tolerant. Other such ovens use a switch mounted at the rear of the oven that is actuated by engagement of the door with a switch actuator extending between the switch and the front of the oven to enable the motor of the oven latch mechanism. The switch actuator in these ovens is typically mounted near the side of the oven frame to be engaged by the side of the oven door upon door closure.
Through use doors may become warped or bent so that sides of the oven doors do not engage the sides of the frames unless the oven door is pulled-in. A switch actuated by the side of the oven door during closure might not be actuated by a warped or bent oven door. The failure of the oven door to actuate a switch enabling the motor of the lock mechanism can result in a service call on the self-cleaning oven as the self-cleaning function may not implement on demand.
The disclosed oven lock mechanisms position an actuator for a switch enabling the motor driving circuit in the center of the front frame of the oven so that the actuator is engaged by the center of the oven door upon closure. Thus door warpage is not as likely to disable the self-cleaning feature of the oven. In the illustrated embodiments, the switches enabling the motor drive circuit of the oven cleaning mechanism are located at the rear of the oven away from the high temperatures present adjacent the oven compartment opening.
According to one aspect of the disclosure, an oven locking mechanism for a self-cleaning oven is provided. The oven includes an oven compartment having an opening defined by a top frame wall, a bottom frame wall and side frame walls. The oven includes an oven door having a top wall, a bottom wall and side walls configured to close the oven compartment. The top walls of the oven frame and the oven door have a central region displaced from the side walls. The oven locking mechanism comprises a latch, an electromechanical actuator, a switch, a plunger and a switch actuator. The latch is mounted to extend forwardly beyond the central region of the top wall of the oven frame to engage a portion of the door located in the central region when moved into a latched position. The electromechanical actuator is coupled to the latch for moving the latch to the latched position when actuated. The switch is electrically coupled to the electromechanical actuator and configured to enable the electromechanical actuator when in a first state and disable the electromechanical actuator when in a second state. The switch is mounted to the oven away from the opening. The plunger is mounted in the central region of the top wall of the frame for movement relative to the frame. The plunger has a door engaging end which when the plunger is in a first position extends forward beyond the frame of the oven in a position to be engaged by a portion of the door in the central region of the top wall during closure of the oven door. The switch actuator is configured to change the state of the switch between the first and second states based on the position of the plunger.
In another aspect of the disclosed device, an oven lock mechanism is provided for a self-cleaning oven having a front, a rear and a front opening oven compartment and an oven door configured to close the oven compartment. The lock mechanism comprises a latch mechanism, a switch and a switch actuator mechanism. The latch mechanism latches the door by engaging a portion of the door. The latch mechanism includes a latch, an electromechanical actuator, and drive circuitry. The latch is mounted for movement relative to the oven frame between a first position in which the oven door opens and closes freely without being inhibited by the latch and a second position in which the latch inhibits opening a closed oven door. The electromechanical actuator is coupled to the latch for moving the latch between the first and the second positions. The drive circuitry is configured to selectively drive the electromechanical actuator. The switch is electrically coupled to the drive circuitry and configured to enable the drive circuitry when in a first state and disable the drive circuitry when in a second state. The switch is mounted to the oven at the rear of the oven. The switch actuator mechanism includes a plunger and a switch actuator. The plunger is mounted to the front of the oven for movement relative to the oven. The plunger has a door engaging end which when the plunger is in a first position extends forward beyond the frame of the oven in a position to be engaged by a portion of the oven door during closure of the oven door. The switch actuator mechanism is configured to change the state of the switch between the first and second states based on the position of the switch plunger. The plunger and latch are mounted to engage a portion of the door not seriously affected by door warpage or bending.
According to yet another aspect of the disclosed device, an oven lock mechanism is provided for an oven having a front opening oven compartment having a back wall and side walls, a top frame wall disposed above the oven compartment and having a central portion displaced from the side walls and a door configured to close the oven compartment by pivoting from an open to a closed position. The lock mechanism comprises front and rear mounting plate portions, a latch, a motor, a switch and a switch actuating mechanism. The front mounting plate portion is mounted to the center portion of the top frame wall. The rear mounting plate portion is mounted to the back wall of the oven compartment. The latch is pivotally mounted to the front mounting plate portion. The latch comprises a latch hook extending forwardly beyond the top frame wall. The latch is configured to pivot between a latched position wherein the latch hook engages and inhibits pivotal movement of the door and an unlatched position wherein the latch does not inhibit pivotal movement of the door. The motor is coupled to the latch to move the same between the latched and unlatched positions when driven. The switch is configured to enable the motor to be driven when in a first state and disable the motor from being driven when in a second state. The switch is mounted to the rear mounting plate portion. The switch actuating mechanism includes an engagement portion and an actuator portion. The engagement portion is mounted for movement relative to the front mounting plate portion and configured to engage and be moved by the door during pivotal movement of the door. The actuator portion is coupled to the engagement portion and configured to change the state of the switch from the second state to the first state in response to movement of the engagement portion.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.